Hundreds of pounds of jewellery was stolen from the Warren James store in the centre during the break-in at around 9pm on Sunday.
The thieves used a hammer to smash a display window of the store and bundled the jewellery into a bag.
Insp Dave Bugg, of the Castleford neighbourhood policing team (NPT), said: “This is a particularly serious crime and follows a slight increase in the number of commercial burglaries around the town centre over the past few weeks. We want to try and nip it in the bud before it becomes a bigger problem.
“We’ve had some other shops and businesses broken into and while we’re not sure if they are linked to this incident we want to put a stop to it.”
Insp Bugg said the thieves got into the centre by using a hammer to smash the glass in a door at the Carlton Street entrance.
They made their way to the Warren James shop where it is suspected they used the same hammer to smash a display window. They put the jewellery into a holdall and fled.
They are both described as white, of average build aged between 20 and 40, wearing dark clothing, one possibly carrying a hammer.
Insp Bugg added: “I would ask for anyone with any information or who saw anyone acting suspiciously at the time to get in touch.”
Anyone with any information should call Castleford NPT on 101 or call Crimestoppers, anonymously, on 0800 555111.